title: Vaccination induced antibodies to recombinant avian influenza A virus M2 protein or synthetic M2e peptide do not bind to the M2 protein on the virus or virus infected cells.
abstract: BACKGROUND
  Influenza viruses are characterized by their highly variable surface proteins HA and NA. The third surface protein M2 is a nearly invariant protein in all Influenza A strains. Despite extensive studies in other animal models, this study is the first to describe the use of recombinant M2 protein and a peptide coding for the extracellular part of the M2 protein (M2e) to vaccinate poultry.
  
  
  METHODS
  Four groups of layer chickens received a prime-boost vaccination with recombinant M2 protein, M2e, a tetrameric construct from M2e peptide bound to streptavidin and a control tetrameric construct formulated with Stimune adjuvant.
  
  
  RESULTS
  We determined the M2-specific antibody (Ab) responses in the serum before vaccination, three weeks after vaccination and two weeks after booster, at days 21, 42 and 56 of age. The group vaccinated with the M2 protein in combination with Stimune adjuvant showed a significant Ab response to the complete M2 protein as compared to the other groups. In addition an increased Ab response to M2e peptide was found in the group vaccinated with the M2e tetrameric construct. None of the vaccinated animals showed seroconversion to AI in a commercial ELISA. Finally no Ab's were found that bound to M2 expressed on in vitro AI infected MDCK cells.
  
  
  CONCLUSIONS
  Although Ab's are formed against the M2 protein and to Streptavidin bound M2e peptide in a tetrameric conformation these Ab's do not recognize of M2 on the virus or on infected cells.
authors.affiliation: Department of Farm Animal Health, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584 Utrecht CL, The Netherlands.
authors.forename: Willem J C
authors.initials: WJ
authors.lastname: Swinkels
authors.forename: Jeroen
authors.initials: J
authors.lastname: Hoeboer
authors.forename: Reina
authors.initials: R
authors.lastname: Sikkema
authors.forename: Lonneke
authors.initials: L
authors.lastname: Vervelde
authors.forename: A D P
authors.initials: AD
authors.lastname: Koets
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood* / Q000378:metabolism; D000956:Antigens, Viral / Q000276:immunology* / Q000378:metabolism; D002645:Chickens; D009980:Influenza A virus; D007252:Influenza Vaccines / Q000008:administration & dosage / Q000276:immunology*; D011485:Protein Binding; D014614:Vaccines, Synthetic / Q000008:administration & dosage / Q000276:immunology; D014763:Viral Matrix Proteins / Q000276:immunology* / Q000378:metabolism; D000086082:Viroporin Proteins
chemical_list: D000914:Antibodies, Viral; D000956:Antigens, Viral; D007252:Influenza Vaccines; D014614:Vaccines, Synthetic; D014763:Viral Matrix Proteins; C488937:M2 protein, Influenza A virus; D000086082:Viroporin Proteins